1. Field of the Invention
The present invention relates generally to a semiconductor fabrication process, and more particularly to a real-time fault detection and classification system in use with a semiconductor fabrication process.
2. Description of Related Art
In order to keep competitive manufacturing ability, semiconductor manufacturers are decreasing manufacturing cost of semiconductor components by 25-30% each year. As pointed out by International Technology Roadmap for Semiconductors (ITRS), four possible methods for reducing manufacturing cost include reducing feature sizes, increasing wafer diameter, improving product yield and increasing overall equipment effectiveness (OEE). As to current semiconductor technology, increasing wafer diameter and improving product yield can at most reduce 3% of the manufacturing cost, and decreasing feature sizes can reduce about 12% to 14% of the manufacturing cost. However, according to an estimation of the Semiconductor Manufacturing Technology Consortium (SEMATECH), equipment efficiency of semiconductor manufacturers only reaches 40-50%. Therefore, to decrease the manufacturing cost by 25-30% each year, the overall equipment efficiency should be improved for decreasing the manufacturing cost by 9-15% instead of 3-10%. It can be expected that in the near future increasing the overall equipment efficiency will play a key role in semiconductor fabrication processes.
To increase the overall equipment efficiency, international semiconductor manufacturers and research institutes such as AMD, IBM, INTEL, MOTOROLA, OAK, SAMSUNG, TI and SEMATECH have made R&D on factory and metrology integration system and automation monitoring system, particularly advanced process control (APC) technique, e.g. U.S. Pat. No. 6,836,691 entitled “Method and Apparatus for Filtering Metrology Data Based on Collection Purpose” and proposed by AMD. The APC technique mainly comprises functions of data collection and data pre-process, fault detection and classification (FDC) and feedback/feed forward run-to-run control (R2R), through which unexpected equipment stop times can be reduced and real-time fault detection on semiconductor tools can be facilitated, thus decreasing occurrence of defective products and protecting quality of semiconductor components from being affected by drifting of features of the semiconductor tools.
As shown in FIG. 1, a conventional fault detection and classification system 1 comprises a computer integrated manufacturing (CIM) host 11, a semiconductor tool 13 and a facility monitoring control system (FMCS) 14. Therein, both the CIM host 11 and the semiconductor tool 13 adopt the SEMI equipment communication standard (SECS) set by the Semiconductor Equipment and Material International (SEMI), while status data received by the facility monitoring control system 14 is in conformity with object linking and embedded (OLE) or open database connectivity (ODBC). Therefore, workers on the CIM host 11 need to master both the SECS and the OLE or ODBC at the same time for analyzing the status data transferred by the semiconductor tool 13 and the facility monitoring control system 14 so as to correctly determine equipment health conditions of the semiconductor tool 13 and the facility monitoring control system 14.
Moreover, in the conventional fault detection and classification system 1, the CIM host 11 can only passively receive status data transferred from the semiconductor tool 13 and the facility monitoring control system 14. In other words, the semiconductor tool 13 or the facility monitoring system 14 may be already abnormal before the CIM host. 11 receives status data of the semiconductor tool 13 or the facility monitoring system 14. Therefore, workers on the fault detection and classification system 1 cannot timely maintain the semiconductor tool 13 or the facility monitoring control system 14. Accordingly, semiconductor fabrication processes using the conventional fault detection and classification system 1 can result in a poor product yield.